The new barge has an early dominator 12s-  Any body have thoughts or info on these pumps- I was looking on American Turbine's site and they have all these upgrades and hp kits - just looking for the low down on these pumps-

When you say early is it a Mar-Bud Casting? They are great pumps and very strong (thick castings).   Early Dominators aren't all that different than late Dominators, the mixing bowl has been improved through the years as have the impellers.  New models come standard with a 17-4 Race strenght shaft, and an HP Bearing kit. Rebuild kits are readilly available.  Replacement wear rings are available with a 1" skirts to use a standard American Turbine impeller now.  The exit side of the original bowl can be opened up from 5.5" to 6.25" to help them flow better (especially when coupled with a droop). 

Warning: The original glacier bearings in these bowls are water lubricated also, which is fine, but the bowl is prone to severe cracking when the bushings and sleave are pressed out.

Thanks Josh- it does say mar-bud on the serial tag.  It all looks pretty original as of now- no snoot or diverter- yet- I don't really know the history of the pump so I am trying to prepare for the worst- Can the older pumps be update to accept the stainless shaft, HP Bearings, and newer style impellers or is it better to go with the american turbine impellers- sorry for all the questions- thanks for all the answers

American Turbine is Dominator, so any impeller your going to buy from them is going to be the same casting, they just cut the wearring skirt down from standard  1" to 3/4" if you were to use the original style wear ring.  However if you are going to rebuild it with a new impeller it only makes scence to replace the wear ring with the modern style. The shaft you have is stainless, it's just a standard grade of stainless.  To upgrade to the HP bearing kit would not be, IMO, putting your money in the best place, the standard replacement bearing is going to last you and do everything you want it to do up to huge HP#. 
-Josh